The present invention relates to a ring generator wheel of the type used in ophthalmic lens grinding. More specifically, the present invention relates to a ring generator wheel with improved coolant flow.
In today's ophthalmic market plastic lenses have replaced glass lenses in all but a few specialized applications. The primary market for glass lenses which are generated today are photochromic glass lenses. Generating of photochromic glass has lead to two readily apparent problems in the industry. First, photochromic glass is a much tougher material to grind than normal plastic lens materials and the like, and therefore, generator wheels are subject to excessive wear under normal operating conditions. Second, the spoilage rate for photochromic lenses is much higher than normal glass lenses in that a higher percentage of the lenses are heat cracked during generation of the lens curvatures. Thus, with the cost of materials and the spoilage rate high there has been a need for improved generating system for glass lenses, and in particular, photochromic lenses.